Reclosers are utilized in power distribution systems at transmission line electrodes to automatically close interrupter switches after they have opened due to a fault. Such interrupters may be used, for example, in utility power-transmission systems or power-distribution systems for railway or industrial plants. A recloser includes a three-phase switch and may employ two voltages sensors per phase leg for monitoring voltage on the input and output transmission lines of the recloser. One voltage sensor monitors the input line to a switch for one phase leg, and another voltage sensor monitors the output line from the switch for the same phase leg. Thus, internal voltage sensors are located on both sides of the interrupter for each phase leg.
A recloser controller may be housed in a frame a distance from a recloser switch. This distance may depend on the amount of electrical insulation needed to isolate the recloser controller relative to the high-voltage recloser switch. The recloser controller receives voltages sensed by the voltage sensors via a control cable. Low energy analog voltage levels may be detected in each sensor utilizing a passive voltage divider circuit, for example, a capacitor network or components that form a capacitor network. The voltage divider circuit may be designed to measure a specified low energy output voltage (Vs) relative to earth ground. This low energy voltage is used to determine a high voltage (HV) level of the transmission line relative to ground. For example, a line input value of HV=10 kilovolts (kV), could ideally yield a sensed output Vs=1 volt (V), for a ratio of HV/Vs=10 k/1.